Earthquakes, tsunamis and floods can kill many people and damage buildings. In
contrast, the effect size for natural and semi-natural landscapes is often small or
negligible. Similarly the impact of climate change may be much worse for people
living at the coast than for coastal ecosystems that are adopted to wind and water
dynamics such as tsunamis, currents, tides and storms since for millenia or even
longer periods of time.
According to IUCN Red List (2019; accessed 4/2020) agriculture, forestry and
aquaculture comprise by far the most threatening activities for habitats and species
on Earth. 31,030 species are threatened worldwide (categories CR, EN, VU), 6523
are critically endangered (CR).
Biological resource use including logging and wood harvesting, hunting,
collecting wild plant material, fishing and harvesting aquatic resources is the second
largest threat. Biological resource use is the most important threat to the oceans, and
the second most important threat for organisms on terrestrial lands.
Alien species are species that live outside their former natural distribution, i.e., in
regions where they have been introduced. Invasive species are those alien or native
species that displace other species and become dominant. In many cases a rapidly
growing population in a region where a species is not native has the effect of
changing species compositions and structures (ecosystem engineering). However,
the influences and effects on ecosystems are diverse. For example, goats or rats on
islands where the relating ecological niche was not filled before the introduced
species occurred may cause the loss of native species such as ground-breeding
birds or vascular plants. An example is the arrival of annual grasses to the worlds
deserts and semi-deserts, which create a persistent fuel source, in contrast to the
ephemeral native annuals that blow away once they have dessicated, and therefore
carry fires in ecosystems that are not adapted to fire.
The introduction of thousands of alien species in continental Europe in contrary is
not documented to have caused the loss of any native species yet. The reason for a
lower risk might be the combination of a much larger region and the former
occupation of niches (cf. Tilman 2004; Ehrenfeld 2010).
Climate change and severe weather events take an intermediate position compared to other threats, in most cases. Changing precipitation rate will in many cases
have a stronger influence on ecosystems and ecosystem services than changing
temperatures. Decreasing temperatures and precipitation rates might have a stronger
influence on ecosystems than increasing values. The reason for this assumption is the
distribution pattern of biodiversity across the Earth with a high species diversity
towards high precipitation rates and temperatures in the tropics and only few biota
living in dry and cold regions. Notably it is also true that biotic interactions increase
towards the tropics (e.g., herbivory, predation, etc.) and a lack of climatic change in
deep time is a presumed driver for these phenomena (Hargreaves et al. 2019).
Geological events including volcanism, earthquakes, tsunamis, avalanches and
landslides take the last position as a threat for all habitat types. Thus, the threat exists,
but does not play an important role compared to many human activities.
Change: Risks and Predictability
187
contrast, the effect size for natural and semi-natural landscapes is often small or
negligible. Similarly the impact of climate change may be much worse for people
living at the coast than for coastal ecosystems that are adopted to wind and water
dynamics such as tsunamis, currents, tides and storms since for millenia or even
longer periods of time.
According to IUCN Red List (2019; accessed 4/2020) agriculture, forestry and
aquaculture comprise by far the most threatening activities for habitats and species
on Earth. 31,030 species are threatened worldwide (categories CR, EN, VU), 6523
are critically endangered (CR).
Biological resource use including logging and wood harvesting, hunting,
collecting wild plant material, fishing and harvesting aquatic resources is the second
largest threat. Biological resource use is the most important threat to the oceans, and
the second most important threat for organisms on terrestrial lands.
Alien species are species that live outside their former natural distribution, i.e., in
regions where they have been introduced. Invasive species are those alien or native
species that displace other species and become dominant. In many cases a rapidly
growing population in a region where a species is not native has the effect of
changing species compositions and structures (ecosystem engineering). However,
the influences and effects on ecosystems are diverse. For example, goats or rats on
islands where the relating ecological niche was not filled before the introduced
species occurred may cause the loss of native species such as ground-breeding
birds or vascular plants. An example is the arrival of annual grasses to the worlds
deserts and semi-deserts, which create a persistent fuel source, in contrast to the
ephemeral native annuals that blow away once they have dessicated, and therefore
carry fires in ecosystems that are not adapted to fire.
The introduction of thousands of alien species in continental Europe in contrary is
not documented to have caused the loss of any native species yet. The reason for a
lower risk might be the combination of a much larger region and the former
occupation of niches (cf. Tilman 2004; Ehrenfeld 2010).
Climate change and severe weather events take an intermediate position compared to other threats, in most cases. Changing precipitation rate will in many cases
have a stronger influence on ecosystems and ecosystem services than changing
temperatures. Decreasing temperatures and precipitation rates might have a stronger
influence on ecosystems than increasing values. The reason for this assumption is the
distribution pattern of biodiversity across the Earth with a high species diversity
towards high precipitation rates and temperatures in the tropics and only few biota
living in dry and cold regions. Notably it is also true that biotic interactions increase
towards the tropics (e.g., herbivory, predation, etc.) and a lack of climatic change in
deep time is a presumed driver for these phenomena (Hargreaves et al. 2019).
Geological events including volcanism, earthquakes, tsunamis, avalanches and
landslides take the last position as a threat for all habitat types. Thus, the threat exists,
but does not play an important role compared to many human activities.
Change: Risks and Predictability
187